What do the following two equations represent? $2x-5y = 5$ $20x+8y = -5$
Answer: Putting the first equation in $y = mx + b$ form gives: $2x-5y = 5$ $-5y = -2x+5$ $y = \dfrac{2}{5}x - 1$ Putting the second equation in $y = mx + b$ form gives: $20x+8y = -5$ $8y = -20x-5$ $y = -\dfrac{5}{2}x - \dfrac{5}{8}$ The slopes are negative inverses of each other, so the lines are perpendicular.